Semi-orthogonal multiple access (SOMA) is a candidate technique for transmission of signals that is being considered by the Third Generation Partnership Project (3GPP). A discussion of SOMA is provided in U.S. patent application Ser. No. 14/589,676, filed Jan. 5, 2015, titled “SYSTEM AND METHOD FOR SEMI-ORTHOGONAL MULTIPLE ACCESS”, the entirety of which is hereby incorporated by reference.
SOMA is based on non-linear superposition coding of transmission signals from paired user equipment (UEs). This typically requires that the paired UEs share the same constellation domain. Thus, there is a challenge in pairing UEs operating in different transmission modes, such as UEs that use spatial multiplexing (e.g., UEs operating in transmission mode 3 (TM3)) and UEs that do not (e.g., UEs operating in transmission mode 2 (TM2)), which do not share the same constellation domain.